Coping style and stress hormone responses in genetically heterogeneous rats: Comparison with the Roman rat strains

Sira Díaz-Morán, Marta Palència, Carme Mont-Cardona, Toni Cañete, Gloria Blázquez, Esther Martínez-Membrives, Regina López-Aumatell, Adolf Tobeña, Alberto Fernández-Teruel

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52 Citations (Scopus)

Abstract

The purpose of the present study was to evaluate for the first time the stress-induced hypothalamus-pituitary-adrenal (HPA), adrenocorticotropic hormone (ACTH), corticosterone and prolactin responses of the National Institutes of Health genetically heterogeneous rat stock (N/Nih-HS rats) in comparison with responses of the relatively high and low stress-prone Roman Low- (RLA-I) and High-Avoidance (RHA-I) rat strains. The same rats were also compared (experiment 1) with respect to their levels of unconditioned anxiety (elevated zero-maze test), novelty-induced exploratory behavior, conditioned fear and two-way active avoidance acquisition. In experiment 2, naive rats from these three strains/stocks were evaluated for " depressive-like" behavior in the forced swimming test. N/Nih-HS and RLA-I rats showed significantly higher post-stress ACTH, corticosterone and prolactin levels than RHA-I rats. N/Nih-HS rats also presented the highest context-conditioned freezing responses, extremely poor two-way avoidance acquisition and very low novelty-induced exploratory behavior. Experiment 2 showed that, compared to RHA-I rats, N/Nih-HS and RLA-I rats displayed significantly less struggling (escape-directed) and increased immobility responses in the forced swimming test. Factor analysis of data from experiment 1 showed associations among behavioral and hormonal responses, with a first factor comprising high loadings of elevated zero-maze variables and lower loadings of conditioned fear, two-way avoidance acquisition and hormonal measures, while a second factor mainly grouped conditioned fear and two-way avoidance acquisition with novelty-induced exploration and post-stress prolactin. Thus, regarding their anxiety/fearfulness, passive coping style, " depressive-like" and stress-induced hormonal responses the N/Nih-HS rats resemble the phenotype profiles of the relatively high-anxious and stress-prone RLA-I rat strain. © 2011 Elsevier B.V.
Original languageEnglish
Pages (from-to)203-210
JournalBehavioural Brain Research
Volume228
DOIs
Publication statusPublished - 1 Mar 2012

Keywords

  • Anxiety
  • Behavioral-hormonal associations
  • Fear
  • Genetically heterogeneous rats
  • Hypothalamus-pituitary-adrenal responses
  • Roman rat strains

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